package com.apache.netty.heartbeat;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.timeout.IdleStateHandler;

import java.util.concurrent.TimeUnit;

public class MyServer {
  public static void main(String[] args) throws Exception {

    // 创建两个线程组
    EventLoopGroup bossGroup = new NioEventLoopGroup(1);
    EventLoopGroup workerGroup = new NioEventLoopGroup(); // 8个NioEventLoop
    try {

      ServerBootstrap serverBootstrap = new ServerBootstrap();

      serverBootstrap.group(bossGroup, workerGroup);
      serverBootstrap.channel(NioServerSocketChannel.class);
      serverBootstrap.handler(new LoggingHandler(LogLevel.INFO));
      serverBootstrap.childHandler(
          new ChannelInitializer<SocketChannel>() {
            @Override
            protected void initChannel(SocketChannel ch) throws Exception {
              ChannelPipeline pipeline = ch.pipeline();
              // 加入一个netty 提供 IdleStateHandler
              /**
               * 说明 1. IdleStateHandler 是netty 提供的处理空闲状态的处理器
               *     2. long readerIdleTime : 表示多长时间没有读,就会发送一个心跳检测包检测是否连接
               *     3. long writerIdleTime : 表示多长时间没有写, 就会发送一个心跳检测包检测是否连接
               *     4. long
               * allIdleTime : 表示多长时间没有读写, 就会发送一个心跳检测包检测是否连接
               *
               * <p>5. 文档说明 triggers an {@link IdleStateEvent} when a {@link Channel} has not
               * performed read, write, or both operation for a while. 6. 当 IdleStateEvent 触发后 ,
               * 就会传递给管道 的下一个handler去处理 通过调用(触发)下一个handler 的 userEventTiggered , 在该方法中去处理
               * IdleStateEvent(读空闲，写空闲，读写空闲)
               */
              pipeline.addLast(new IdleStateHandler(7000, 7000, 10, TimeUnit.SECONDS));
              // 加入一个对空闲检测进一步处理的handler(自定义)
              pipeline.addLast(new MyServerHandler());
            }
          });

      // 启动服务器
      ChannelFuture channelFuture = serverBootstrap.bind(7000).sync();
      channelFuture.channel().closeFuture().sync();

    } finally {
      bossGroup.shutdownGracefully();
      workerGroup.shutdownGracefully();
    }
  }
}
